rhai/codegen/src/module.rs
2021-12-21 22:16:03 +08:00

322 lines
10 KiB
Rust

use quote::{quote, ToTokens};
use syn::{parse::Parse, parse::ParseStream};
#[cfg(no_std)]
use core::mem;
#[cfg(not(no_std))]
use std::mem;
use std::borrow::Cow;
use crate::attrs::{AttrItem, ExportInfo, ExportScope, ExportedParams};
use crate::function::ExportedFn;
use crate::rhai_module::ExportedConst;
#[derive(Debug, Clone, Eq, PartialEq, Hash, Default)]
pub struct ExportedModParams {
pub name: String,
skip: bool,
pub scope: ExportScope,
}
impl Parse for ExportedModParams {
fn parse(args: ParseStream) -> syn::Result<Self> {
if args.is_empty() {
return Ok(ExportedModParams::default());
}
Self::from_info(crate::attrs::parse_attr_items(args)?)
}
}
impl ExportedParams for ExportedModParams {
fn parse_stream(args: ParseStream) -> syn::Result<Self> {
Self::parse(args)
}
fn no_attrs() -> Self {
Default::default()
}
fn from_info(info: ExportInfo) -> syn::Result<Self> {
let ExportInfo { items: attrs, .. } = info;
let mut name = String::new();
let mut skip = false;
let mut scope = None;
for attr in attrs {
let AttrItem { key, value, .. } = attr;
match (key.to_string().as_ref(), value) {
("name", Some(s)) => {
let new_name = s.value();
if name == new_name {
return Err(syn::Error::new(key.span(), "conflicting name"));
}
name = new_name;
}
("name", None) => return Err(syn::Error::new(key.span(), "requires value")),
("skip", None) => skip = true,
("skip", Some(s)) => return Err(syn::Error::new(s.span(), "extraneous value")),
("export_prefix", Some(_)) | ("export_all", None) if scope.is_some() => {
return Err(syn::Error::new(key.span(), "duplicate export scope"));
}
("export_prefix", Some(s)) => scope = Some(ExportScope::Prefix(s.value())),
("export_prefix", None) => {
return Err(syn::Error::new(key.span(), "requires value"))
}
("export_all", None) => scope = Some(ExportScope::All),
("export_all", Some(s)) => {
return Err(syn::Error::new(s.span(), "extraneous value"))
}
(attr, _) => {
return Err(syn::Error::new(
key.span(),
format!("unknown attribute '{}'", attr),
))
}
}
}
Ok(ExportedModParams {
name,
skip,
scope: scope.unwrap_or_default(),
})
}
}
#[derive(Debug)]
pub struct Module {
mod_all: syn::ItemMod,
fns: Vec<ExportedFn>,
consts: Vec<ExportedConst>,
sub_modules: Vec<Module>,
params: ExportedModParams,
}
impl Module {
pub fn set_params(&mut self, params: ExportedModParams) -> syn::Result<()> {
self.params = params;
Ok(())
}
}
impl Parse for Module {
fn parse(input: ParseStream) -> syn::Result<Self> {
let mut mod_all: syn::ItemMod = input.parse()?;
let fns: Vec<_>;
let mut consts = Vec::new();
let mut sub_modules = Vec::new();
if let Some((_, ref mut content)) = mod_all.content {
// Gather and parse functions.
fns = content
.iter_mut()
.filter_map(|item| match item {
syn::Item::Fn(f) => Some(f),
_ => None,
})
.try_fold(Vec::new(), |mut vec, item_fn| -> syn::Result<_> {
let params =
crate::attrs::inner_item_attributes(&mut item_fn.attrs, "rhai_fn")?;
let f =
syn::parse2(item_fn.to_token_stream()).and_then(|mut f: ExportedFn| {
f.set_params(params)?;
f.set_cfg_attrs(crate::attrs::collect_cfg_attr(&item_fn.attrs));
#[cfg(feature = "metadata")]
f.set_comments(crate::attrs::doc_attributes(&mut item_fn.attrs)?);
Ok(f)
})?;
vec.push(f);
Ok(vec)
})?;
// Gather and parse constants definitions.
for item in content.iter() {
match item {
syn::Item::Const(syn::ItemConst {
vis,
ref expr,
ident,
attrs,
ty,
..
}) if matches!(vis, syn::Visibility::Public(_)) => consts.push((
ident.to_string(),
ty.clone(),
expr.as_ref().clone(),
crate::attrs::collect_cfg_attr(&attrs),
)),
_ => {}
}
}
// Gather and parse sub-module definitions.
//
// They are actually removed from the module's body, because they will need
// re-generating later when generated code is added.
sub_modules.reserve(content.len() - fns.len() - consts.len());
let mut i = 0;
while i < content.len() {
match content[i] {
syn::Item::Mod(_) => {
let mut item_mod = match content.remove(i) {
syn::Item::Mod(m) => m,
_ => unreachable!(),
};
let params: ExportedModParams =
crate::attrs::inner_item_attributes(&mut item_mod.attrs, "rhai_mod")?;
let module = syn::parse2::<Module>(item_mod.to_token_stream()).and_then(
|mut m| {
m.set_params(params)?;
Ok(m)
},
)?;
sub_modules.push(module);
}
_ => i += 1,
}
}
} else {
fns = Vec::new();
}
Ok(Module {
mod_all,
fns,
consts,
sub_modules,
params: ExportedModParams::default(),
})
}
}
impl Module {
pub fn attrs(&self) -> &[syn::Attribute] {
&self.mod_all.attrs
}
pub fn module_name(&self) -> &syn::Ident {
&self.mod_all.ident
}
pub fn exported_name(&self) -> Cow<str> {
if !self.params.name.is_empty() {
(&self.params.name).into()
} else {
self.module_name().to_string().into()
}
}
pub fn update_scope(&mut self, parent_scope: &ExportScope) {
let keep = match (self.params.skip, parent_scope) {
(true, _) => false,
(_, ExportScope::PubOnly) => matches!(self.mod_all.vis, syn::Visibility::Public(_)),
(_, ExportScope::Prefix(s)) => self.mod_all.ident.to_string().starts_with(s),
(_, ExportScope::All) => true,
};
self.params.skip = !keep;
}
pub fn skipped(&self) -> bool {
self.params.skip
}
pub fn generate(self) -> proc_macro2::TokenStream {
match self.generate_inner() {
Ok(tokens) => tokens,
Err(e) => e.to_compile_error(),
}
}
fn generate_inner(self) -> Result<proc_macro2::TokenStream, syn::Error> {
// Check for collisions if the "name" attribute was used on inner functions.
crate::rhai_module::check_rename_collisions(&self.fns)?;
// Extract the current structure of the module.
let Module {
mut mod_all,
mut fns,
consts,
mut sub_modules,
params,
..
} = self;
let mod_vis = mod_all.vis;
let mod_name = mod_all.ident.clone();
let (_, orig_content) = mod_all.content.take().unwrap();
let mod_attrs = mem::take(&mut mod_all.attrs);
if !params.skip {
// Generate new module items.
//
// This is done before inner module recursive generation, because that is destructive.
let mod_gen = crate::rhai_module::generate_body(
&mut fns,
&consts,
&mut sub_modules,
&params.scope,
);
// NB: sub-modules must have their new items for exporting generated in depth-first order
// to avoid issues caused by re-parsing them
let inner_modules = sub_modules
.drain(..)
.try_fold::<_, _, Result<_, syn::Error>>(Vec::new(), |mut acc, m| {
acc.push(m.generate_inner()?);
Ok(acc)
})?;
// Regenerate the module with the new content added.
Ok(quote! {
#(#mod_attrs)*
#mod_vis mod #mod_name {
#(#orig_content)*
#(#inner_modules)*
#mod_gen
}
})
} else {
// Regenerate the original module as-is.
Ok(quote! {
#(#mod_attrs)*
#mod_vis mod #mod_name {
#(#orig_content)*
}
})
}
}
#[allow(dead_code)]
pub fn name(&self) -> &syn::Ident {
&self.mod_all.ident
}
#[allow(dead_code)]
pub fn consts(&self) -> &[ExportedConst] {
&self.consts
}
#[allow(dead_code)]
pub fn fns(&self) -> &[ExportedFn] {
&self.fns
}
#[allow(dead_code)]
pub fn sub_modules(&self) -> &[Module] {
&self.sub_modules
}
#[allow(dead_code)]
pub fn content(&self) -> Option<&[syn::Item]> {
match self.mod_all {
syn::ItemMod {
content: Some((_, ref vec)),
..
} => Some(vec),
_ => None,
}
}
}